1. Field of the Invention
The present invention relates to a method of testing a spliced portion of optical fibers spliced by fusion-splicing so as to eliminate defective products having large splicing losses at the spliced portions.
2. Description of the Related Art
Optical fibers can be spliced by fusion-splicing as follows. Two optical fibers are aligned such that the mating ends of the exposed fiber portions oppose each other and are spaced apart from each other by a predetermined distance. The ends of the exposed fiber portions are heated by, e.g., discharge heating. When the ends of the exposed fiber portions are melted, the optical fibers are pushed toward each other by a predetermined distance so that the ends of the exposed fiber portions abut against each other. These ends are kept heated until they are completely fusion-spliced. Products having large splicing losses which are regarded as defective products often result from fusion-splicing. Splicing defects are found when light is transmitted through the fusion-spliced optical fiber and its optical transmission loss is measured.
If splicing defects are detected by transmitting a light through the fusion-spliced optical fiber and measuring the transmission loss, these operations are time-consuming and cumbersome. Systematic and efficient splicing operations of optical fibers on working spots cannot be expected.